A liquid crystal display device (LCD) displays an image by aligning a nematic or smectic liquid crystal compound in a certain direction and switching the alignment by applying voltage. A process for manufacturing an LCD is a highly expensive process having complicated procedures, thereby requiring installation of large production lines and facilities.
In the methods presented in order to solve the problems regarding the process for manufacturing an LCD, a so-called polymer dispersed liquid crystal (PDLC, the term PDLC used in this specification refers to a so-called superordinate concept including polymer network liquid crystals (PNLCs) or polymer stabilized liquid crystals (PSLCs)) device, which is realized by dispersing liquid crystals in a polymer matrix, has been known in the related art. Since the PDLCs may be manufactured by coating a liquid crystal solution, the PDLCs may be obtained through a simple process.
A liquid crystal compound is generally present so that the liquid crystal compound is not aligned in the PDLCs. Therefore, the PDLCs remain opaque when a voltage is not applied to the PDLCs. When a voltage is applied to the PDLCs, the liquid crystal compound is aligned according to the alignment of the PDLCs. As a result, the PDLCs become transparent. This indicates that the switching between opacity and transparency is possible. However, the PDLCs have a considerably reduced contrast ratio, compared to typical LCDs in which white and black are switched between two polarizing plates.